1. Field of the Invention
This invention relates to apparatus for testing and/or calibrating a detector such as a thermal imaging device which may be attached to a missile or other projectile.
2. Description of the Prior Art
It has been proposed to test the imaging capabilities of a thermal imager by providing standard test scene plates for different test wavelengths. This technique is somewhat limited in that the test scene plates have to be changed for different wavelength ranges, which may impart a non-uniformity in the testing of the thermal imager.
It has also been proposed to test thermal imagers in situ in the field, this is also not wholly satisfactory. At different times of the day slight differences in conditions would render comparison of a number of thermal imagers inaccurate.
A third proposal has been to simulate a scene either by computer or electronically. As this requires a plurality of individually controlled elements it has proved both complex and costly.